Any time the ECO symbol is on the dash your running 4cyc no way to turn it off unless you use a tuner like the Trinity from Diablo Sport
Some years and versions don't have that little symbol available as an option any more.
e.g. current 2014 UConnect.
Bummer, as it would be a source of amusement on cross country drives to either try to keep it on--or off as the muse strikes one.
I'd actually prefer a less subtle indicator such as turning the display a tree hugger green or something.
The pistons are still moving so they would be getting lube. The valves are shut to create an air spring effect. Never heard of long term maintenance issues with MDS and it IS one way to extend the sales life of larger engines until they are banned forever.
Does anyone know if it changes the set of 4 cylinders it deactivates to keep from any possible effects by always using the same ones? It would be trivial to implement, but that doesn't mean it would occur to anyone to do so.